How much energy does a heat pump use?

Based on an EnergySage analysis of a Department of Energy database, a typical heat pump in a typical home uses 5,475 kilowatt hours (kWh) per year—easily the single biggest energy-user in most houses. That’s enough electricity to run nine full-size fridges year round, or power a Tesla Model 3 for 15,000 miles. 

But there's really no such thing as a typical house, so if you install a heat pump, the energy use will probably look much different than that average we cited, depending on the building, climate, and the particular heat pump. The likely range is somewhere between 400 kWh and 22,500 kWh, according to our analysis.

What about the power draw at any given moment? The most popular heat pump on the EnergySage Marketplace (a 3-ton cold-climate Mitsubishi) can draw anywhere between 830 W and 6.9 kW of power, depending on the weather and other factors—though it’ll spend most of its time closer to the bottom of that scale. Small mini-splits for a single room might draw as little as a few hundred watts, while the largest, least-efficient models consistently pull 7.5 kW.

Those are some huge ranges. Below, we’ll walk you through a few ways to estimate how much energy a heat pump will use in your particular home.

According to the Department of Energy, more than half of a typical household’s energy use goes toward heating and cooling. While a heat pump is far more energy-efficient than a traditional heating system (and many air conditioners, too), it’ll still be the most energy-hungry appliance in almost any home that uses one as the main HVAC system.

The exact amount depends heavily on the following factors.

• Local climate: Cold winters and hot, humid climates drive up a home’s energy demand. Look up your climate zone on the 2021 IECC map below, or on the IECC website.

• Home size: Bigger homes generally use more energy for heating and cooling.

• Home layout: Box-shaped buildings are more efficient than sprawling estates.

• Home weatherization: Better insulation and fewer air leaks help save energy.

• Existing HVAC system: Leaky or undersized ductwork can drive up your energy costs. Ductless heat pumps can be more efficient than ducted systems.

• Thermostat setpoint: Every degree you turn up your thermostat tends to use 3% more energy, according to a University of Georgia study.

• The heat pump and installer: Heat pumps aren't all equally efficient, and sub-optimal installation makes a big difference, too.

The most accurate way to estimate a heat pump’s energy use is to do a load calculation, then model the energy use based on the weather in your climate. This is tricky to do without training, and even HVAC contractors are usually pretty shy about providing these estimates. A fee-based home performance consultant is most likely to give you an accurate number here, and they can also account for any insulation upgrades you might perform as well.

But if you want to make a free, good-enough estimate, you can either:

• Look at estimates based on similar homes. We’ll provide a wide range of these estimates in the next section. 

• Tally up your previous heating and cooling bills, and adjust for a heat pump’s efficiency. More on that a little further down this page.

Based on our analysis of data from the Department of Energy’s ResStock database, here’s how much electricity a typical heat pump is likely to use across different houses and different climates when it’s the sole heating and cooling system. Smaller houses, houses with compact layouts, houses with better insulation and air sealing, and homes in multi-family buildings are all more likely to be in the lower percentiles. The opposite is true for larger, draftier, more sprawled-out houses.

(Note: The ResStock database relies on IECC climate zone definitions from 2004, which are slightly different from the 2021 zones. Zone 7 was previously divided into 7A and 7B, but that’s no longer the case. Zone 5C, which is new as of 2021, and Zone 8 are not represented in the ResStock database.)

Whole-house, average-efficiency, heat-pump energy estimates

Heating efficiency: sCOP 2.5. Cooling efficiency: SEER 15. Lower percentiles are more likely to represent smaller, more-efficient homes. Cities are examples, not the full sample. Units in kWh.

Notice the huge spread even within climate zones. Higher-demand homes in a given climate zone (the 90th percentile) often need 5x and up to nearly 10x the electricity of a low-demand home (10th percentile).  

Here are the heating-only numbers. Those low numbers are not typos—some homes don’t use heat. Again, these figures assume that all of the heating would be handled by a heat pump that’s appropriate for the climate. Homes with hybrid heating systems (heat pump plus a backup) would consume more energy overall, though they’ll often cost less to install and to operate.

Whole-house estimates, heat only

Same details as previous chart.

Here are the cooling-only figures. One note: In the original data set, many of the homes in colder climates only used partial-home cooling. We normalized it to whole-house cooling here because when people get whole-house AC (as you would if you relied entirely on a heat pump for heating), they tend to use it.

Whole-house estimates, cooling only

Same details as previous chart.

What if the efficiency is better or worse than average?

Our estimates reflect what field studies tend to find when they measure the performance of today’s leading high-efficiency, high-performance, all-climate heat pumps: The real world results do not match the official efficiency ratings, and they’re a bit less efficient than the most optimistic predictions. 

Across a typical heating season, a heat pump tends to run at around 250% efficiency (sCOP 2.5), compared to 100% efficiency for traditional electric resistance heat, or 80% for a low-end gas furnace. Advocates often cite 300% (sCOP 3.0) or greater as a typical heating efficiency. The official HSPF (heating efficiency) ratings also suggest that the efficiency should be better than 250%. That’s all possible, particularly in mild climates, but it’s not the norm

As for the SEER rating (cooling efficiency), we chose SEER 15 instead of SEER 18 or an even higher rating for a few reasons: 1) It’s the minimum legal SEER as of 2023. 2) Lower-SEER heat pumps can make a lot of sense in humid climates because they tend to be better at dehumidification, and those are the parts of the country where cooling systems run the most. 3) In the real world, cooling efficiency doesn’t live up to the official rating, so even if you buy a higher-SEER heat pump, it’ll probably underperform its nameplate.

Why do heat pumps usually fall short of their predicted efficiency? It’s usually improper system design and installation. Ducts could be leaky or too small, or the heat pump could be the wrong size, or the contractor could have made a mistake on one of the many, many important steps to a proper installation.

Here’s what the median energy use could look like in better- or worse-case scenarios.

Median heat pump energy use, various efficiencies

Another way to look at it is by “energy intensity,” or the amount of electricity you’ll need per square foot of your living space.

The national median is 3.84 kWh per square foot per year, but again, that varies substantially depending on the climate, as well as the characteristics of your home and existing HVAC system.

Heat pump energy intensity estimates

Heating efficiency: sCOP 2.5. Cooling efficiency: SEER 15. Lower percentiles are more likely to represent homes with better insulation and weatherization. Cities are examples, not the full sample. Units in kWh / sq. ft.

It’s another way to estimate how much energy a whole-house system would need. You can also use it to roughly estimate how much energy a partial-home system will use, like a mini-split that only serves one floor, or a bonus room for example. 

Example: If you’re in zone 5A and need a mini-split to cover a 500 square foot home addition, the energy use assuming the median energy intensity would be: 5.87 * 500 = 2,935 kWh. 

In practice, it’s a lot more nuanced than this. Home additions and bonus rooms often have greater heating and cooling loads than rooms in the main part of the house, for example. So try multiplying your square footage by higher and lower intensity percentiles to give yourself a likely range of energy demand.

This takes a bit of work, but it could be more accurate than the estimates above because you don't have to guess at which percentiles your home sits in. You’ll need to know:

• How much energy you used (or money you spent) on heating and cooling. This can be a little tricky to isolate, because lots of other energy uses are baked into your utility bills. One easy-ish workaround: Look at how much energy you use in months when your HVAC doesn’t run much (or at all), and estimate from there.  

• How efficient your current heating and cooling equipment is. It should be on a sticker or badge somewhere. If you can’t find it, fossil-fuel furnaces and boilers are usually somewhere between 75% to 90% efficient (the AFUE rating), though it can be as high as 98%. Traditional electric heat is always 100% efficient. Most ACs currently in operation are rated somewhere between SEER 10 and 14, though they can get up to SEER 20 or greater.  

• How efficient a new heat pump is likely to be. This will always be a flawed estimate. But for the sake of simplicity, assume that a new heat pump will be about 250% efficient during the heating season (sCOP 2.5), and run at SEER 15 during the cooling season. 

• The cost of energy. Your most recent utility bills should give you the most accurate cost per kWh of electricity, therm of gas, or gallon of oil or propane.

There are tons of heating and cooling cost calculators floating around on Google, though not all of them are very accurate. The best one we’ve found for heating is hosted by Efficiency Maine—just make sure to enter all the important numbers under the “show details” checkbox. For cooling, this SEER Energy Savings calculator has proven to be correct every time we’ve checked its math.

The simplest answer is to take the estimated annual energy use from above and multiply it by your cost per kWh of electricity. For most people most of the time, that’s about what it’ll cost. Here are some estimates, based on prices in cities in various climate zones as of August 2023.

Heat pump operating cost estimates

Electricity price source. Average heat pump efficiency.

If you own solar panels, or you’re on a time-of-use plan with your electric company (this is rare outside of California), then the numbers get fuzzier. 

We cover the details for solar in another article. But basically, you need to figure out how much of a heat pump’s energy use you can offset with solar, and then multiply the remainder by the cost of grid energy. 

Time-of-use is tricky because the cost changes throughout the day; you tend to need AC the most when electricity costs the most, though the opposite is true during the heating season. That said, multiplying your estimated energy use by the average cost of electricity should get you a decent estimate.

So far, we've been talking about total energy use (in kilowatt-hours). For most people, kWh is the most important measurement because it lets you estimate the stuff that affects your finances: How much it'll cost to run, or how many solar panels you’d need to offset the energy use.

A heat pump’s power draw (in watts or kilowatts, no hours) is a different measurement that tells you how much electricity it draws in a given moment. It doesn't directly affect your utility bills, but it does have some implications for the installation, and possibly your home's electrical system:

• What circuit breaker and wiring gauge you’ll need. It’s typically between 15 amps and 50 amps on a two-pole circuit, and between a 10-gauge to a 6-gauge wire. Since these are critical safety specs, they’re always listed on a heat pump’s submittal sheet.

• Whether your home’s electrical service can handle the demands of a heat pump. If your heat pump will draw 40 amps, and you have a suite of other 240-volt electric appliances (e.g., electric stove, clothes dryer, water heater, EV charger) your home probably needs 200 amps of electrical service or a creative circuit-sharing setup. If your heat pump will rarely draw more than 25 amps and you’ve put your home on a watt diet, your home might be fine with 100 amps.

• How much output you’d need from a home battery or generator. Your backup system should have enough output (in kW) to handle the momentary spike in power that heat pumps pull when they first turn on. You can find it on a heat pump spec sheet, expressed as the locked-rotor amperage (LRA). If the generator or battery can handle that initial jolt, it can also supply the heat pump mid-cycle, when it’s pulling less power. (Whether it has the capacity to keep the heat pump running for very long is a separate question.)

Figuring out the precise mid-cycle power draw (not the startup spike) is very easy for basic, lower-efficiency single-stage heat pumps that you'd often find in warm climates, or in some hybrid heat pump setups.

It's not very easy difficult for high-performance, all-climate, inverter-driven mini-split heat pumps.

Basic, single-stage heat pumps

Single-stage heat pumps are either all the way on, or all the way off. When they’re on, they always pull the same amount of power. 

The easiest way to figure out the power draw is to divide the size of the heat pump (measured in BTU), by the heat pump’s efficiency ratings.

Cooling wattage = BTU / SEER

Heating wattage = BTU / HSPF

It’s that simple. The only tricky part is that in 2023, the HVAC industry switched over to SEER2 to measure cooling efficiency, and HSPF2 for heating efficiency.

These new specs are supposed to represent the real-world energy use more accurately, which is a good thing.

A good-enough rough calculation is that you can multiply the SEER2 rating by 1.05 to get the equivalent original SEER rating, and the HSPF2 rating by 1.17 to get the equivalent original HSPF rating.

Single-stage heat pump power draw, cooling mode

Single-stage heat pump power draw, heating mode

Inverter heat pumps, on the other hand, can have hundreds or even thousands of settings, each with distinct power draw. Those settings can change minute to minute as the indoor and outdoor temperatures shift, or if you make adjustments to your thermostat. So it’s very hard to pinpoint exactly how much power an inverter heat pump will use at any given moment.

You can use the same tricks as above to calculate an inverter heat pump’s maximum power draw—but it’ll rarely ever run at those top settings. This type of heat pump is designed to run almost constantly, at a relatively low setting. 

A popular 3.5-ton Mitsubishi cold-climate heat pump, for example, can crank all the way up to 6,900 watts (6.9 kW) when it’s -13 F degrees, the house is really struggling to hold heat, and the outdoor unit needs to defrost itself regularly. But when it’s “only” 17 F, the Mitsubishi can draw as little as 830 W (0.83 kW) in between defrost cycles. Most of the time, particularly in cooling mode, it’ll be somewhere in the middle, probably in the range of 1,000 to 3,500 watts (1 to 3.5 kW). The only way to know for certain is with an energy monitoring system.

The best resource we’ve found to get an idea of a heat pump’s range of potential power draw is the cold-climate heat pump database managed by the Northeast Energy Efficiency Partnerships. (It’s great for tons of other heat pump research, too.) The vast majority of inverter-driven heat pumps are on there, so you should be able to find what you need.

One of the best ways to save money with a heat pump is to pair it with solar power, so it runs on free electricity. When you register for the EnergySage Marketplace, you can ask for quotes on rooftop solar, a home battery, and a heat pump installation. (It’s free to register, and we’ll never share your contact info without your permission.) Vetted, experienced installers will compete for your business, and our independent Energy Advisors are available to help you sort through your best options. 

Can’t get a rooftop system? We also have a Marketplace for community solar farm subscriptions, where you can nab a healthy discount on your utility bills with no upfront costs, all while supporting local clean energy projects.

Image: Midjourney